A174071 Numbers that can be written as a sum of at least 4 consecutive positive squares.
30, 54, 55, 86, 90, 91, 126, 135, 139, 140, 174, 190, 199, 203, 204, 230, 255, 271, 280, 284, 285, 294, 330, 355, 366, 371, 380, 384, 385, 415, 446, 451, 476, 492, 501, 505, 506, 510, 534, 559, 595, 615, 620, 630, 636, 645, 649, 650, 679, 728, 730, 734, 764
Offset: 1
Keywords
Examples
30=1^2+2^2+3^2+4^2, 54=2^2+3^2+4^2+5^2, 55=1^2+2^2+3^2+4^2+5^2, ...
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
N:= 1000: # to get all terms <= N Res:= NULL: for m from 4 while m*(m+1)*(2*m+1)/6 <= N do for k from 1 do v:= m*(6*k^2 + 6*k*m + 2*m^2 - 6*k - 3*m + 1)/6; if v > N then break fi; Res:= Res, v; od od: sort(convert({Res},list)); Robert Israel, May 06 2019 -
Mathematica
max=60^2;lst={};Do[z=n^2+(n+1)^2+(n+2)^2;Do[z+=(n+x)^2;If[z>max,Break[]];AppendTo[lst,z],{x,3,Sqrt[max]/2}],{n,Sqrt[max]/2}];Union[lst]
Extensions
Edited by Robert Israel, May 06 2019
Comments